Technical Field
Aspects of this disclosure relate to a method of making a piezoelectric film, a method of making a piezoelectric element, a liquid discharge head, and an image forming apparatus.
Description of the Related Art
Lead zirconate titanate (compositional formula: Pb(Zrx , Ti1−x)O3, hereinafter PZT) is a solid solution of lead zirconate (compositional formula: PbZrO3, hereinafter PZO) and lead titanate (compositional formula: PbTiO3, hereinafter PTO or PT), and has a highest piezoelectric property in a composition near a phase boundary between tetragonal and rhombohedral systems.
Here, the crystal structure of PZT is a perovskite structure and has a high dielectric constant, a large piezoelectricity, and a ferroelectricity. PZT is typically used for, for example, actuators or sensors by utilizing its piezoelectricity. PZT is also used for, e.g., ferroelectric memories (FeRAMs) by utilizing the ferroelectricity.
Examples of a method of making a piezoelectric film (piezoelectric thin-film layer) include a sputtering method and a chemical solution deposition (CSD) method. The CSD method is advantageous in that composition can be more precisely controlled and a larger film area can be uniformly formed at a lower cost than any other method.
It is known that, when a piezoelectric film made of PZT is (100)-oriented, the piezoelectric element has a best piezoelectric performance. Hence, the orientation is controlled by utilizing various crystallized seed layers made of, e.g., PbTiO3 (PTO) or LaNiO3 (LNO).